While I have a great deal of interest in this subject I have been too busy to do much with it here on this site. Below are the first few paragraphs of the Wikipedia listing for eschatology. I gave a speech in Helen Georgia on the threat of plagues, biological warfare and emergent diseases that i will post the transcript to as a separate topic to kick things off.

Eschatology ⁱ/ˌɛskəˈtɒlədʒi/ (from the Greek ἔσχατος/ἐσχάτη/ἔσχατον, eschatos/eschatē/eschaton meaning "last" and -logy meaning "the study of", first used in English around 1550)^[1] is a part of theology, philosophy, and futurology concerned with what are believed to be the final events of history, the ultimate destiny of humanity — commonly referred to as the end of the world or the "World to Come."

The Oxford English Dictionary defines eschatology as "concerned with ‘the four last things: death, judgment, heaven, and hell’".^[2]

In the context of mysticism, the phrase refers metaphorically to the end of ordinary reality and reunion with the Divine. In many religions it is taught as an existing future event prophesied in sacred texts or folklore. More broadly, eschatology may encompass related concepts such as the Messiah or Messianic Age, the end time, and the end of days.